Street-network Sprawl in Sud, Cameroon

What is Street-network sprawl?

Street-network Sprawl is a way to measure urban sprawl, worldwide, through the connectedness of the streets. Less sprawl means more connected, more walkable streets. Well-connected streets – like New York City’s grid – are more walkable and can be served by public transit.

The street network is permanent, and its connectivity affects the livability and environmental footprint of cities for decades and centuries to come. In places with more connected streets, residents drive less and walk more. A well-connected street network is associated with better outcomes for health, the environment, sustainable consumption, social integration, and equity.

We can quantify how connected street networks are with the Street Network Disconnectedness Index (SNDi).

SNDi -- our measure of street-network sprawl (disconnectedness)

The SNDi is a comprehensive measurement of “sprawl”. It captures:

A higher SNDi means less-connected streets – i.e., more sprawl. For the 10137 cities in our dataset, the average SNDi is 2.25, with half of the cities' SNDis falling between 1.08 and 3.25.

More information on the sprawl index can be found in these research papers:

To see the state of street-network sprawl across the globe, visit the sprawlmap.

Sud: region in Cameroon

What exactly constitutes the spatial extent of the city? For these aggregations, we used the Global Human Settlement Layer Urban Center Database (GHS-UCDB) to define the boundaries of the city. These cities -- or urban centers -- cover areas that are densely populated and built-up, and so may extend beyond the spatial borders of these cities that we may be familiar with. The GHS area is shaded in blue.

View Sud, Cameroon on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Sud as of 2014, the overall level of street-network sprawl is 5.19, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 4.96, 5.43, 5.15 and nan. Data was not available in 2001-2014.

Quantity of street network construction: The street network in Sud spans a total of 6940 kilometers. It is dominated by roads constructed in 1991-2000. These roads have an SNDi of 5.15, which is highly disconnected.

Effect on the aggregate network: New construction in each period adds to the total stock of streets, but does not change streets that have already been built. Therefore, it has a limited effect on the street network as a whole. The SNDis of the aggregate street network in the respective time periods are 4.96, 5.28, 5.09 and 5.19. Disconnectivity in Sud's street network follows a zig-zag trend. In 1975, the region was most disconnected; while it was most connected in 1976-1990.

The level of street-network sprawl in new development in Sud followed a zig-zag trend. To get a sense of how street development has changed in Sud, we can consider three of its most populous cities: Kribi, Ebolowa and Djoum. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in new development in Kribi followed a zig-zag trend. The level of street-network sprawl in new development in Ebolowa followed a zig-zag trend. The level of street-network sprawl in new development in Djoum followed a zig-zag trend.

How do development practices in Sud fare in comparison to others in Cameroon? out of the 11 regions in Cameroon. Its position in the ranks since 1975 has fallen; relative to other regions in Cameroon, street construction in Sud has become more connected. Sud ranked 2nd in 1975, 1st in 1976-1990 and 3rd in 1991-2000. There was no ranking in 2001-2014 due to unavailable data.

As of 2014, the city with the most disconnected street network in Sud is Ebolowa with an SNDi of 5.3, which is highly disconnected. Conversely, the most connected city is Djoum with an SNDi of -0.43, which is very well-connected. See trends for these cities: Djoum, Ebolowa

The level of street-network sprawl in the aggregate network in Sud followed a zig-zag trend with an overall increase. To get a sense of how the aggregate street network has changed in Sud, we can consider three of its most populous cities: Kribi, Ebolowa and Djoum. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in the aggregate network in Kribi followed a zig-zag trend. The level of street-network sprawl in the aggregate network in Ebolowa fell steadily. The level of street-network sprawl in the aggregate network in Djoum rose steadily.

To date, Sud is the 2nd-most disconnected out of the 11 regions in Cameroon. Its position in the ranks since 1975 has not changed. Sud ranked 2nd in 1975, 1st in 1976-1990, 2nd in 1991-2000 and 2nd in 2001-2014.